This invention relates to a centrifugal clutch assembly, and specifically to a centrifugal clutch assembly that is controllable for tailoring clutch torque to current vehicle operating conditions.
Typically, an automatic clutch assembly includes a plurality of centrifugal weights that move radially outward in response to rotation. Radial movement of the centrifugal weights is translated into axial movement of a corresponding reaction surface. Radial movement of the centrifugal weights corresponds with rotational speed of the clutch assembly to begin clutch actuation. Typically, clutch actuation begins within a substantially narrow and fixed range of rotational speed.
Once the centrifugal clutch is engaged, the only way to disengage the clutch is to decrease rotational speed. The rotational speed of the clutch assembly corresponds to actuation of an accelerator pedal. As the accelerator pedal is actuated, the clutch begins to engage and transfer torque. Torque transfer increases with rotational speed according to a fixed relationship. This relationship holds regardless of current vehicle conditions. The fixed relationship causes different vehicle start off characteristics for different vehicle conditions. An unloaded vehicle may start off too quickly, whereas a fully loaded vehicle may start off sluggishly.
Transmission shifting requires torque transmission to be momentarily interrupted to release torque lock between gears. Conventional centrifugal clutch assemblies often include an auxiliary clutch to release torque lock and facilitate gear changes. Additional clutch mechanisms complicate manufacture and operation, and can reduce dependability and durability.
Accordingly, it is desirable to develop a centrifugal clutch assembly that is adaptable to differing vehicle operating conditions and can accommodate transmission gear changes to provide consistent vehicle performance.